fix(public): do not expose coupon code after preregistration

Codes are still created and stored for Mailwizz; JSON response omits
coupon_code. Thank-you UI explains email delivery instead of showing code.

Made-with: Cursor

resources/js/app.js

@@ -420,7 +420,6 @@ document.addEventListener('alpine:init', () => {
         redirectSecondsLeft: null,
         redirectTimer: null,
         strings: config.strings || {},
-        couponCode: '',
 
         copyPageLink() {
             const url = this.pageShareUrl;
@@ -435,19 +434,6 @@ document.addEventListener('alpine:init', () => {
             });
         },
 
-        copyCouponCode() {
-            const code = this.couponCode;
-            if (!code) {
-                return;
-            }
-            navigator.clipboard.writeText(code).then(() => {
-                this.copyFeedback = this.strings?.couponCopied || '';
-                setTimeout(() => {
-                    this.copyFeedback = '';
-                }, 2500);
-            });
-        },
-
         init() {
             if (this.phase === 'before') {
                 this.tickCountdown();
@@ -566,8 +552,6 @@ document.addEventListener('alpine:init', () => {
                 if (res.ok && data.success) {
                     this.phase = 'thanks';
                     this.thankYouMessage = data.message ?? '';
-                    this.couponCode =
-                        typeof data.coupon_code === 'string' && data.coupon_code !== '' ? data.coupon_code : '';
                     this.startRedirectCountdownIfNeeded();
                     return;
                 }